How to make GMM tests appear in stargazer?

Question

I am doing a lot of GMM regressions and need to report all tests. I'm using plm and stargazer package for this.

However, stargazer does not provide this tests directly, so I wrote a long code to add this tests.

I would like to provide the name of the equations to a function which makes all this tests and adds them directly in stargazer. can someone help me to build this function? I believe it will help many people with the same problem. :-)

library(plm)
library(stargazer)
library(stringr) 

data("EmplUK")
#these are my two GMM equations, "z1" and "z2" - from PLM manual
## Arellano Bond 91 table 4b 
z1 <- pgmm(dynformula(log(emp)~log(wage)+log(capital)+log(output),list(2,1,0,1)),
           data=EmplUK, effect="twoways", model="twosteps",
           gmm.inst=~log(emp),lag.gmm=list(c(2,99)))

## Blundell and Bond tab4 (cf DPD for OX p.12 col.4)
z2 <- pgmm(dynformula(log(emp)~log(wage)+log(capital),list(1,1,1)),
           data=EmplUK, effect="twoways", model="onestep",
           gmm.inst=~log(emp)+log(wage)+log(capital),lag.gmm=c(2,99),
           transformation="ld")

###########################################
#saving results of equation z1 and z2 - i would like to make a function on this part 
#########################################
Z1_summary<-summary(z1,robust=TRUE)
Z2_summary<-summary(z2,robust=TRUE)

#saving instruments
Z1_inst <- "~log(emp),lag.gmm=list(c(2,99))"
Z2_Inst <- "~log(emp)+log(wage)+log(capital),lag.gmm=c(2,99)"

Instruments <- c("Instr",Z1_inst,Z2_Inst)

#saving sargan results
sargan_est <- c("Sargan",
                round(Z1_summary$sargan$statistic,4),
                round(Z2_summary$sargan$statistic, 4))

sargan_p <- c("Sargan (p-value)",
              round(Z1_summary$sargan$p.value, 4),
              round(Z2_summary$sargan$p.value, 4))

good_sargan<-c("Conclusion about Sargan",
              ifelse(round(Z1_summary$sargan$p.value, 4)>0.05, "Good", "Bad"),
              ifelse(round(Z2_summary$sargan$p.value, 4)>0.05, "Good", "Bad"))

#saving ar1 results
AR1_est <- c("AR(1)",
             round(Z1_summary$m1$statistic, 2),
             round(Z2_summary$m1$statistic, 2))

AR1_pvalue <- c("AR(1) p-value",
                round(Z1_summary$m1$p.value, 4),
                round(Z2_summary$m1$p.value, 4))

#saving ar2 results
AR2_est <- c("AR(2)",
             round(Z1_summary$m2$statistic, 2),
             round(Z2_summary$m2$statistic, 2))

AR2_pvalue <- c("AR(2) p-value",
                round(Z1_summary$m2$p.value, 4),
                round(Z2_summary$m2$p.value, 4))

#saving wald results
Wald_Coef_est <- c("Wald Coef (df)",
       str_c(round(Z1_summary$wald.coef$statistic, 2),    " (", Z1_summary$wald.coef$parameter, ")"),
       str_c(round(Z2_summary$wald.coef$statistic, 2),    " (", Z2_summary$wald.coef$parameter, ")")
                   )

Wald_Coef_pvalue <- c("Wald Coef p-value",
                       round(Z1_summary$wald.coef$p.value, 4),
                       round(Z2_summary$wald.coef$p.value, 4))

Wald_Tim_est <- c("Wald Time (df)",
       str_c(round(Z1_summary$wald.td$statistic, 2),    " (", Z1_summary$wald.td$parameter, ")"),
       str_c(round(Z2_summary$wald.td$statistic, 2),    " (", Z2_summary$wald.td$parameter, ")")
                  )

Wald_Tim_pvalue <- c("Wald Time p-valor",
       round(Z1_summary$wald.td$p.value, 4),
       round(Z2_summary$wald.td$p.value, 4))

###########################
#showing results with stargazer

stargazer(z1,z2,
          column.labels = c("Eq z1", "Eq z2"),
          title= "2 GMM equations",
          align = TRUE,
          type = "text",
          digits = 4,
          no.space = TRUE,
          add.lines = list(Instruments,
                           sargan_est,
                           sargan_p,
                           good_sargan,
                           AR1_est,
                           AR1_pvalue,
                           AR2_est,
                           AR2_pvalue,
                           Wald_Coef_est,
                           Wald_Coef_pvalue,
                           Wald_Tim_est,
                           Wald_Tim_pvalue),
          notes="Sargan is considered good (acceptable) if its p-value is above 5%")